Re: [PATCH] tpm2-sessions: Fix out of range indexing in name_size

[Jarkko Sakkinen <jarkko@kernel.org>]

On Thu, Jan 08, 2026 at 02:31:59PM +0200, Jarkko Sakkinen wrote:
> [ Upstream commit 6e9722e9a7bfe1bbad649937c811076acf86e1fd ]
> 
> 'name_size' does not have any range checks, and it just directly indexes
> with TPM_ALG_ID, which could lead into memory corruption at worst.
> 
> Address the issue by only processing known values and returning -EINVAL for
> unrecognized values.
> 
> Make also 'tpm_buf_append_name' and 'tpm_buf_fill_hmac_session' fallible so
> that errors are detected before causing any spurious TPM traffic.
> 
> End also the authorization session on failure in both of the functions, as
> the session state would be then by definition corrupted.
> 
> Cc: stable@vger.kernel.org # v6.10+
> Fixes: 1085b8276bb4 ("tpm: Add the rest of the session HMAC API")
> Reviewed-by: Jonathan McDowell <noodles@meta.com>
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---

This is for v6.12.

BR, Jarkko